The present invention pertains to grade measurement devices, also referred to as leveling or surveying rods, and their uses, and more particularly to direct read-type leveling rods, such as are used in conjunction with laser beam or optical-sight type leveling instruments in construction applications, including excavation, setting and checking grades, measuring, and the like.
Construction projects, including for instance road construction, home building, general excavating, etc., often require leveling tasks to be carried out by unskilled workers. Such tasks include, but are not limited to, checking pavement and concrete grades, setting concrete forms, erecting building components at varying elevations, etc.
In conventional construction projects, it has previously been known to employ leveling instruments, such as optical sights or laser-beam leveling instruments, to take elevation measurements of existing elevations, and to establish measurements for desired elevations, at various locations on the construction site. According to this methodology, the leveling apparatus is initially set up and adjusted to a level position, and the elevation of the sighting portion of the leveling apparatus is determined relative to some assumed base, sea level for instance. A leveling rod is provided, usually having a graduated measuring scale. A reading made from the thus-adjusted leveling instrument to the vertically oriented leveling rod as a lower end thereof rests on the ground at a desired location will yield a measure of the vertical distance from the elevation of the leveling instrument to the base of the leveling rod. Subtracting from this distance the height of the leveling instrument above the assumed base (e.g., sea level) yields a measure of the elevation of the ground, relative to the assumed base, at the lower end of the leveling rod. The disclosure of Martin, U.S. Pat. No. 1,220,358, is exemplary in these regards, and is incorporated herein by reference in its entirety.
Oftentimes, survey stakes or like markers are employed in construction projects to provide benchmark elevations following elevation measurements conducted in the manner discussed above. The survey stakes are provided at selected locations on the construction site where ground elevations have been previously determined. Taking the predetermined, desired elevation for that location, and a measurement of the height of the survey stake relative to the existing ground elevation, a measurement is provided on the stake that reflects the requisite change in the existing ground elevation to achieve the desired elevation.
While initial elevation surveys are commonly carried out by skilled professionals, subsequent leveling tasks (e.g., altering existing elevations to correspond to desired elevations, making subsequent elevation measurements, etc.), are carried out by relatively unskilled laborers, also using leveling rods and leveling instruments.
According to the use of conventional leveling instruments in establishing desired elevations at one or more locations for example, it is necessary for a worker to place a lower end of the leveling rod on a previously-identified benchmark, such as the aforementioned survey stake, having identified in relation thereto a known measurement for establishing the desired elevation at each location. The worker is first required to calibrate the leveling rod to the benchmark by placing the lower end of the leveling rod on the benchmark elevation and thereafter aligning the leveling instrument with a xe2x80x9czeroxe2x80x9d or other established starting point on the graduated measuring scale. The leveling rod is thereafter adjusted so that the known measurement reflecting the adjustment necessary to establish the desired elevation is identified on the graduated measuring scale, and necessary modifications to the elevation at the location until the measurement reflecting the desired elevation on the leveling instrument is aligned with the leveling instrument.
In the past, optical-sight type leveling instruments were employed to take visual sightings of leveling rods in conjunction with efforts to determine desired elevations such as in the manner described above. In modern construction projects, however, laser-beam leveling instruments are more frequently employed instead of optical sights. One such apparatus is described in U.S. Pat. No. 4,221,483, issued to Spectra-Physics, Inc., the disclosure of which is incorporated herein in its entirety. These laser-beam leveling instruments transmit a (usually) horizontal laser-beam across the construction site, which laser beam is detected by a laser-beam detector provided on the leveling rod carried by a construction worker. The detector is typically mounted to a bracket that is slidingly positionable along the length of the leveling rod, and is further operative to provide audible and/or visual signals indicating when the detector is positioned along the leveling rod at a height corresponding to elevation of the laser-beam. By selectively positioning the detector on the leveling rod at given measurements for establishing desired elevations, it is possible for a construction worker to use the leveling rod, for example, to determine elevations at various locations on the construction site.
One particularly common use of a leveling rod with leveling apparatus is in excavating operations, where existing terrain on a construction site is modified, either by cutting or filling as necessary, to achieve desired elevations. As indicated, the construction site is typically initially surveyed by skilled personnel who establish desired grade elevations for various locations throughout the site, and who identify these desired elevations on survey stakes or the like as measures of the amount of cut or fill necessary relative to the elevation of the stake, or as measures of the amount of cut or fill relative to some other benchmark elevation. xe2x80x9cCuttingxe2x80x9d or xe2x80x9ccutxe2x80x9d refers to the process of removing material from the existing terrain, for instance by machine or manually, until an elevation is reached that is lower than the existing elevations of the terrain; xe2x80x9cfillingxe2x80x9d or xe2x80x9cfill,xe2x80x9d in contrast, refers to the addition of material to the existing terrain until an elevation is reached that is higher than the existing elevation of the terrain. According to the method described above, the construction worker calibrates the measuring scale of the leveling rod to xe2x80x9czeroxe2x80x9d or some other starting position relative to the benchmark elevation, determines the amount of cut or fill necessary at a given location, for instance as directed by a stake measurement, identifies a position along the measuring scale of the leveling rod corresponding to the amount of cut or fill (either by positioning a visual sighting indicator, when using optical-sight type leveling instruments, or, when laser-beam leveling instruments are employed, by adjusting the position of the laser beam detector), and adjusts the elevation of the terrain as necessary until the position on the leveling rod corresponding to the amount of cut or fill (and hence the desired elevation) is aligned with the leveling instrument.
For relatively unskilled laborers, conventional methods for employing leveling rods and leveling instruments such as described above are unduly complicated, since the determination of one or more desired elevations relative to a previously sighted measurement commonly requires mathematical computation. In the exemplary circumstance of grading the front porch and steps of a residential construction, the task of checking elevations for each step relative to a sighted elevation measurement made for the top of the porch would necessitate adding to that measurement the predetermined height of each step relative to the top of the porch. If any of these calculations is made in error, subsequent measurements made of the step elevations will be incorrect. And in excavating operations, a construction worker may improperly add or subtract one or more cut or fill measurements in relation to the measuring scale provided on the leveling rod, thus yielding an improper elevation at the measured location.
A further problem with conventional leveling rods, already mentioned in passing, is their complex and relatively fragile construction. In these regards, the leveling rod of U.S. Pat. No. 4,392,308, the disclosure of which is incorporated herein in its entirety, is exemplary. That device is characterized by a flexible, endless band comprising a graduated scale, the band mounted for circumvolutionary movement around an elongated rod. A slide mechanism is mounted for longitudinal sliding movement on the elongated rod. The slide mechanism includes a clamp for securing the mechanism to the endless belt to prevent the belt from moving. When the flexible band is broken, as can frequently occur during normal use in a construction environment, the device must be disassembled for repair. Moreover, sand, dirt, cement, and other particulates common to construction environments can foul the mechanism that provides for circumvolutionary movement of the endless band. And in cold climates, ice can hinder operation of the slide mechanism that secures the endless belt against movement.
It would therefore be desirable to provide a leveling rod for conducting leveling tasks, and a method of employing the same, that is at once-economical to manufacture, robust yet simple in design, and uncomplicated in its method of operation.
The present invention addresses and solves the problems discussed above, and encompasses other features and advantages, by providing a leveling rod comprising an elongated base rail member having generally opposing front and rear longitudinal surfaces, generally opposing lateral surfaces, an upper end, and a lower end comprising a foot portion, and an elongated sliding rail member having generally opposing front and rear surfaces, generally opposing lateral surfaces, and upper and lower ends. An elongated, self-supporting measuring insert is removably mateable with the front surface of the sliding rail member. The front surface of the base rail member and the rear surface of the sliding rail member each have one or the other of complementary tongue and groove portions whereby the base and sliding rail members are slidingly interconnected in lapped relation; and the sliding rail member is further selectively fixedly positionable along the base rail member in a plurality of positions.
According to one feature of this invention, at least one of the lateral sides of the sliding rail member further comprises a longitudinally extending, lateral track adapted to slidingly receiving therein a bracket mounting a laser-beam detector, whereby the inventive leveling rod may be used in conjunction with conventional laser-beam leveling instruments.
A method is also disclosed for employing the inventive leveling rod in conjunction with a leveling instrument to establish at least one predetermined elevation relative to a benchmark elevation at one or more locations on a construction site without the need for mathematical computations. According to this method, a leveling rod is provided comprising elongated base and sliding rail members slidingly interconnected in lapped relation, the sliding rail member being selectively fixedly positionable along the base rail member in a plurality of positions, the base rail member having generally opposing front and rear longitudinal surfaces, an upper end, and a lower end comprising a foot portion, and the sliding rail member having generally opposing front and rear surfaces, and upper and lower ends. At least one elongated, self-supporting, blank measuring insert removably mateable with the front surface of the sliding rail member is also provided, the measuring insert having indicia identifying the relative positions of the benchmark elevation and the at least one predetermined elevation, thereby doing away with the performance of any computation by the leveling rod user. Per this method, the leveling rod is calibrated to the benchmark elevation by positioning the foot portion of the leveling rod on the benchmark elevation, and slidingly moving the sliding rail member along the base rail member until the indicia on the measuring insert corresponding to the benchmark elevation is aligned with the leveling instrument, either visually or through the use of a laser-beam leveling instrument. The at least one predetermined elevation may thereafter be established at one or more locations on the construction site by positioning the foot portion of the leveling rod on a support surface at each of the one or more locations, and modifying the elevation of the support surface until the indicia on the measuring insert corresponding to the at least one predetermined elevation is aligned with the leveling instrument, again as may be determined via optical or laser-beam leveling instruments.
Per one feature of this inventive method, the indicia on the measuring insert may comprise non-numeric indicia, alphabetic indicia, or symbolic indicia.
According to one feature of this invention, a cut attachment for a leveling rod, including for example the leveling rod of this invention, is provided to automatically establish a lower elevation at one or more locations on a construction site using a known measurement provided for establishing a higher elevation in relation to a benchmark elevation, where the distance between the lower and higher elevations is constant. The cut attachment includes first and second hingedly connected longitudinal segments, and is characterized by a folded condition, wherein the first and second segments are arranged in lapped relation, and an unfolded condition, wherein the first and second segments are arranged end-to-end. The first segment is adapted for sliding interconnection with a leveling rod, and the first segment is further selectively fixedly positionable along the leveling rod in a plurality of positions. A measuring scale may also be provided on the second segment, whereby a determination of the length of the second segment depending below the foot portion of the leveling rod is more easily determined. Per one feature of this inventive cut attachment, the first and second segments are each provided with complementary, removably-interengageable elements that are interengaged in the folded condition of the cut attachment. These removably-interengageable elements may, according to one embodiment of this invention, comprise a magnet provided on one of the first or second segments, and a magnetically attractable member provided on the other of the first or second segments.
A method for employing the inventive cut attachment is also disclosed, according to which methodology a leveling instrument and a single leveling rod may be employed to automatically establish a lower elevation at one or more locations on a construction site using a known measurement provided for establishing a higher elevation in relation to a benchmark elevation, where the distance between the lower and higher elevations is constant. According to this method, a leveling rod is provided having a measuring scale and a lower end comprising a foot portion. The first segment of the cut attachment is fixedly positioned along the leveling rod such that, in the folded condition of the cut attachment, the second segment does not extend beyond the lower end of the leveling rod, and in the unfolded condition of the cut attachment the second segment extends beyond the lower end of the leveling rod a distance that is equal to the distance between the higher and lower elevations. With the cut attachment in the folded condition thereof, the leveling rod is calibrated with the leveling instrument by placing the foot of the leveling rod on the benchmark elevation, and aligning the leveling instrument with a position on the measuring scale corresponding to a starting position. Thereafter, a position corresponding to the known measurement for establishing the higher elevation is identified on the measuring scale of the leveling rod. With this position identified, the lower elevation may be established at one or more locations on the construction site by placing the cut attachment in the unfolded condition thereof, positioning the foot portion of the second segment on a support surface at the one or more locations, and modifying the elevation at the one or more locations as necessary until the position on the measuring device corresponding to the known measurement for establishing the higher elevation is aligned with the leveling instrument. According to this methodology, the lower elevation may be easily established at a plurality of locations on the construction site where a known measurement is provided to establish a higher elevation in relation to a benchmark elevation by simply calibrating the leveling rod to the benchmark elevation with the cut attachment in the folded condition thereof, identifying the known measurement for establishing the higher elevation, and then unfolding the cut attachment and aligning the known measurement for establishing the higher elevation with the leveling device.
The specification also discloses a measuring attachment for use in conjunction with an elongated leveling rod of the type having a measuring scale, such as the leveling rod of this invention, the measuring attachment comprising a bracket mountable to the leveling rod for longitudinal sliding-movement there along. The bracket, which may comprise a commercially available bracket such as, for example, those mounting laser-beam receivers, includes means for identifying a first position on the measuring scale corresponding to a measurement for establishing a first elevation on the measuring scale. The measuring attachment further includes an elongated rail member extending from the bracket in a direction generally parallel to the axis of movement of the bracket along the leveling rod, the rail member including means for identifying at least a second position that is different from the first position, the means for identifying the at least second position being selectively moveably positionable along the length of the rail.
According to one feature of this invention, the elongated rail member is removably connectable to the bracket.
According to still another feature, the elongated rail member is alternately removably connectable to the bracket in at least a first position, wherein the rail member extends away from the bracket in a first direction generally parallel to the axis of movement of the bracket, and at least a second position, wherein the rail member extends away from the bracket in a second direction.
Means for using the measuring attachment are described whereby both a leveling instrument and a single leveling rod are employed to automatically establish at least a second elevation at one or more locations on a construction site using a known measurement provided for establishing a first elevation in relation to a benchmark elevation, where the distance between the first and second elevations is constant. The method comprises the steps of providing a leveling rod having a lower end comprising a foot portion, and a measuring scale, and further providing a measuring attachment for the leveling rod, the measuring attachment comprising a bracket mountable to the leveling rod and adapted for longitudinal sliding-movement there along, the bracket including means for identifying a first position on the measuring scale corresponding to a measurement for establishing a first elevation, and an elongated rail member extending from the bracket in a direction generally parallel to the axis of movement of the bracket along the leveling rod, the rail member including means for identifying at least a second position on the measuring scale that is different from the first position, the means for identifying the at least second position further being selectively moveably positionable along the length of the rail. The means for identifying the at least second position along the measuring scale are fixedly positioned a predetermined distance from the means for identifying the first position that corresponds to the constant distance between the first and second elevations. The leveling rod is calibrated by placing the foot of the leveling rod on the benchmark elevation, and adjusting the means for identifying the first position to a position on the measuring scale corresponding to a starting position. Thereafter, the means for identifying the first position are adjustably positioned to a position on the measuring scale corresponding to the known measurement for establishing the first elevation in relation to the benchmark elevation. The at least second elevation may thereafter be established at one or more locations by adjusting the means for identifying at least a second position to a position on the measuring scale corresponding to the known measurement for establishing the first elevation in relation to the benchmark elevation, positioning the foot of the leveling rod on a support surface at the one or more locations, and modifying the elevation at the one or more locations as necessary until the means for identifying at least a second position are aligned with the leveling instrument.